"The NACA has conducted a flight investigation to improve the cooling characteristics of the installation of a double-row radial engine. The tests reported herein concern the use of the NACA injection impeller and ducted head baffles in various combinations on both the port inboard and the port outboard engines. The performance of the modified installation was evaluated by comparing it with that of the standard engines" (p. 1).

Report presenting measurements of the velocity distributions at the outlet of a large number of duct elbows of round and elliptical as well as square and rectangular cross section at a range of Reynolds numbers. Special investigations include measurements of the decay of velocity patterns produced by curved ducts and the effect of asymmetrical upstream velocity distributions. Results regarding typical distributions, tabulation of principal results, and special investigations are provided.

Report presenting total-pressure recoveries obtained with four-cone inlet combinations at Mach number 1.85. The configurations tested included a cone designed to produce three oblique shocks ahead of the diffuser inlet combined with two other inlets, a cone generated by a parabolic arc in combination with two other inlets, a cone-inlet combination designed to produce an isentropic entrance flow at 0 degrees angle of attack, and a 30 degree single-shock cone combined with a perforated inlet section. Each of the configurations yielded total-pressure recoveries higher than what was reported in previous testing.

Report presenting an investigation of the effect of tip shape on the aerodynamic characteristics of large-scale 45 degrees swept-forward and 45 degrees swept-back wings. The results show that none of the variations of tip shape investigated nor the addition of bodies of revolution at the tips produced major changes in the characteristics of the swept wings.

Report presenting an aerodynamic-control-effectiveness investigation using free-flight rocket-propelled RM-5 test vehicles at high subsonic, transonic, and supersonic speeds. Results regarding aileron control characteristics and drag measurements are provided.

Report presenting calculated performance characteristics of a ducted rocket with gasoline and liquid oxygen as the fuel mixture and with a mass flow of 1 slug per second. Evaluations of net thrust, frontal area, thrust per unit frontal area, and specific fuel consumption are given for all of the flight conditions under which it might operate.

Report discussing an investigation to determine the drag of a configuration with a body of fitness ratio 12 with stabilizing tail surfaces and a 12-percent-thick 30-degree swept-forward wing using the free-fall method. The drag oft he wing and the total drag were measured separately and compared. The swept-forward wing was found to greatly increase the effect of drag on the body-tail combination.

Report presenting an investigation to obtain a survey of the flying characteristics at low speeds of models with low-aspect-ratio delta wings. Four models with triangular plan-form sweptback wings and five models with the tips cut off to give taper ratios were tested. Results regarding the stability and control characteristics of each of the models is provided.

Report presenting flight measurements obtained during acceptance tests conducted by the Bell Aircraft Corporation on the XS-1 research airplane. The primary focus was on the aerodynamic loads, handling qualities, maximum lift, and buffet boundaries of the airplane.

The effects on dynamic lateral stability and controllability of some of the important aerodynamic and mass characteristics are discussed and methods are presented for estimating the various stability parameters to be used in the calculation of the dynamic lateral stability of airplanes with swept and low-aspect-ratio wings.

Report presenting tests in a pressure tunnel to determine the low-speed pitch characteristics of a 42 degree sweptback wing with circular-arc airfoil sections. Information regarding the characteristics of basic wing, leading-edge flap investigation, and effects of fuselage are provided.

Report presenting an experimental study of the pressure fluctuations at the combustion-chamber inlets of a ramjet operating a Mach number of 1.92 in the supersonic tunnel. Results are presented for two burner configurations of different operating characteristics to indicate trends in pressure magnitude, frequency, and wave form. Results regarding the perforated conical flame holder, regenerative-type burner, and diffuser total-pressure recovery are provided.

Report presenting the results of tests to determine the effect of taper on the zero-lift drag of wings of constant exposed aspect ratio at low supersonic speeds. Findings indicated that maximum thickness, leading-edge, and trailing-edge sweep are all important in determining the drag coefficient of a tapered wing.

Memorandum presenting a method for varying the mass flow of supersonic inlets with a circular cross section and a central body. The method consists of changing the size of the entering stream tube by means of an inflatable boot on the surface of the central body.

Report presenting transonic speed testing utilizing a rocket-powered Bell XS-1 airplane with 10-percent-thick wing and 8-percent-thick horizontal tail. Information is provided for flights up to Mach number 1.06 and altitudes of about 40,000 feet. Results regarding the variation of control-surface positions and forces and sideslip angle with Mach number, time history, rudder effectiveness, and lateral oscillations are provided.

Report presenting an investigation of the characteristics of three representative NACA 1-series nose inlets over a Mach number range extending from 0.4 to 0.925 in the high-speed wind tunnel. Results regarding pressure distribution, drag, and some potential design considerations are provided.

Memorandum presenting the results of measurements of gust and draft velocities within thunderstorms at an air field over a 7-day period. The data are summarized in tables and compared to previous flights.

Report presenting various methods of providing compressor-capacity and pressure-ratio control in the gas-generator type of compound engine over a range of altitudes. The analytical results indicated that the best method of control is that in which the first stage of compression is carried out in a variable-speed supercharger driven by a hydraulic slip coupling. Results regarding the constant-pressure-ratio compressor, constant-volume compressor, comparison of piston-type and rotary compressors, effect of variable-area turbine nozzle, and effect of designing for high altitudes are provided.

Report presenting an investigation to determine the effect of the primary-jet temperature on the performance of several ejector configurations. The performance of ejectors expressed in terms of the ratio of weight of secondary air flow to primary air flow was found to be affected by temperature in two ways.

From Summary: "A sturdy stiffener is defined as a stiffener of such proportions that it does not suffer cross-sectional distortion when moments are applied to some part of the cross section. When such a stiffener is attached to one edge of a plate, it will resist rotation of that edge of the plate by means of its torsional properties. A formula is given for the restraint coefficient provided the plate by such a stiffener. This coefficient is required for the calculation of the critical compressive stress of the plate."

"Test of 10-foot diameter, four and six blade single-rotating and dual-rotating propellers were conducted in the NACA propeller-research tunnel. The propellers were mounted at the front end of a streamline body incorporating spinners to house the hub portions. The effect of a symmetrical wing mounted in the slipstream ranged from 20 degrees to 65 degrees setting corresponds to airplane speeds greater than 500 miles per hour. The results indicate that dual-rotating propellers were from 0 to 6 percent more efficient than single-rotating ones; but, when the propellers operated in the presence of a wing, the gain was reduced by about one-half" (p. 319).

"The effects of propeller operation on the static longitudinal stability of single-engine tractor monoplanes are analyzed, and a simple method is presented for computing power-on pitching-moment curves for flap-retracted flight conditions. The methods evolved are based on the results of powered-model wind-tunnel investigations of 28 model configurations. Correlation curves are presented from which the effects of power on the downwash over the tail and the stabilizer effectiveness can be rapidly predicted" (p. 399).

From Summary: "Tests were made to fill partly the need for information on the effect of afterbody dimensions on the hydrodynamic stability of a flying boat in smooth water. The dimensions investigated were depth of step, angle of afterbody keel, and length of afterbody. An analysis of the data showed that as either the afterbody length or keel angle was increased an accompanying increase in depth of step was required in order to maintain adequate landing stability."

"An iteration method is employed to obtain the flow of a compressible fluid past a curved surface. The first approximation which leads to the Prandtl-Glauert rule, is based on the assumption that the flow differs but little from a pure translation. The iteration process then consists in improving this first approximation in order that it will apply to a flow differing from pure translatory motion to a greater degree. The method fails when the Mach number of the undisturbed stream reaches unity but permits a transition from subsonic to supersonic conditions without the appearance of a compression shock" (p. 305).